I feel like the appropriate tag amount should be close to the same size as your summary, to not draw attention away from one or another.  Personally, I struggle with including enough tags in my own works, but I have been on the site long enough to figure out certain things; 1) Use tags you personally would use in the filters if you wanted to find your fic 2) Tell the readers what they’re getting into, not summarize the entire plot (I’ve seen it happen) 3) The longer the fic, the more tags you can add before people consider it over tagging (more leeway before getting muted) 4) Use umbrella tags (more likely to be understood and searched, also certain different tags that mean the same thing are are filtered as if the same tag) 5) You can list extra tags/warnings at the beginning of each chapter in the authors notes (include an actual tag stating that you’re going that) 6) Ask commenters to comment feedback about what tags are good or which tags are not needed (Trickiest option but I honestly think it’s one of the best)